Dipper teeth



y 4, 1961 L. w. VAN BUSKIRK 2,990,633

DIPPER TEETH Filed Dec. 9, 1953 2 Sheets-Sheet 1 INVENTOR lesler W Zznfllr'ltirlf United States v Patent Easton, a. Filed Dec. 9, 1953, Ser. No. 397,240

' 1 Claim. (Cl. 37-142) My invention relates to improvements in dipper teeth such as are carried by the digging lips of steam shovel dippers, drag buckets and other excavating equipment.

Replacement of digging points of prior art dipper teeth is exceedingly expensive due to the large amount of metal they contain as the means to counteract tendency of such points to curl vertical-1y under digging stresses in service. Another factor in initial prior art tooth cost and in the expense of digging point replacement is the fact that prior art teeth require expensive heavy duty load-sustaining base-to-point securing means to prevent the digging point from turning, under digging stress, about the theoretical horizontal axis provided at the site of tooth point and base connection.

It is therefore the primary object of my invention to reduce initial tooth cost without sacrifice of durability and other service qualtities and also to provide a replaceable digging point which, while containing much less metal than heretofore, will not curl in service and which eliminates the necessity for load-sustaining means for attaching the digging point to its base.

More specifically, the invention contemplates a digging tooth wherein the resultant straight line of digging stressproduced force is transmitted directly from the front edge of the digging point to the nose or mounting portion of the tooth base. This obviates any need for a load-sustaining digging point-to-base fastening because the tendency of the digging point to rock vertically is eliminated.

Another object of the invention is to provide novel digging point reinforcing means which, while preventing vertical curling of same in service, also-reinforces the corners of the digging tip or edge so as to prolong the life of the replaceable digging point.

Various other objects and advantages of the invention will be apparent to those versed in the art upon reference to the accompanying drawings in connection with the descriptive matter appearing hereinafter.

In the drawings showing a now preferred example of my invention, like reference characters have been employed to designate the same parts wherever they a-ppea in h ve vi s. and

FIG. 1 is a fragmentary side elevational view of a dipper tooth embodying my invention, the rear portion of the digger lip-carried base section being broken away;

' FIG..2 is a longitudinal vertical sectional view through the device as'shown in FIG. 1;

FIG. 3 is a sectional view taken on the line 3-3 of FIG. 1;

FIG. 4 is a fragmentary perspective view of the front end of the base section of the tooth and showing the mounting means for the digging point-providing tooth sec tion;

FIG. 5 is a sectional view taken on the line 5-5 of FIG. 1.

Referring to the drawings by reference characters, numeral designates generally the base section of the tooth which provides the rearwardly extending bifurcated portion formed by the arms 12, 13 which define the recess 14 for receiving the dipper lip not shown) in the usual way.

The digging point-providing section or extension of the tooth base 10 comprises the elongated bar-like body 11 which will ordinarily be of the same width as the base section 10, the member 11 providing the digging point 11a at its outer end.

Attachment of the digging point-providing section 1 1 of v 'ice the tooth to the base section 10 is effected by the boss and socket formation 15, 16 best illustrated in FIGS. 2, 4 and 5.

In carrying out the invention in its illustrated form, I provide the base section 10 with the forwardly extending boss 15. The top and bottom surfaces of the base section 10 are indicated at 12a and 1311, respectively, and they taper outwardly in the direction of the shoulders 12b, 13b, respectively, which are located above and below the boss 15. The forward end of the base section 10 also provides the shoulders 20 at opposite sides of the boss 15. w

As indicated in FIGS. 1 and 2, the inner ends of the socket-defining portions 19, 19, 18 and 22 which are located below the lower surface of the mainbody portion 11 of the bar-like digging tip providing section engage shoulders "12b, 13b, 20, 20, so as to cooperate with the outer end of the boss 15 to sustain the digging tip-providing section when in service.

The boss receiving socket 16 of the, digging-tip-providing section 11 is provided by the end wall 17, side walls 19, and bottom wall 18 in conjunction with the undersurface 11b of the main bar-like body portion 11 of the digging tip-providing section.

It is to be noted that the digging tip-providing section 11 provides the shoulder 22 which engages the top shoulder 12b of the base section above the boss 15; and further, that the section 11 terminates in the tail section 23 which overlies the top surface 12a of the base section '10 for a substantial distance rearwardly of the boss 15, as a shield for said surface 12a.

Referring to Fig. 2, it will be noted that the boss 15 makes a snug fit in the socket of member 11. Thus, the end of the boss 15 makes contact with the inner surface 17a of the socket wall 17, which surface is substantially perpendicular to the inner surface 18a of the socket wall 18 which lies closely adjacent the bottom surface of the boss 15. The top wall 15a of the boss 15, by preference, slopes upwardly from the forward end of such boss and lies in close parallel adjacency with the socket-providing bottom surface 11b of the member 11.

As shown in FIGS. 1 and 2, the side shoulders 20 which are provided by the base section 10 at opposite sides of the boss 15 are provided with recess-like seats 20a to receive. correspondingly shaped lug portions 19a which are provided by the socket sides 19. The recited arrangement functions to prevent rocking movement of the member 11 on the boss in case the socket and boss do not make an absolutely nice fit.

As illustrated in FIGS. 1 and 2, the axis of the bar-like digging section 11 is inclined toward the axis of the base section 10 and its forwardly projecting boss 15; and the digging point 11a is located adjacent the prolongation of the longitudinal axis of the base section 10 and its boss 15 The reason for this arrangement will be presently apparent.

In prior art teeth, the digging edge tends to curl and furthermore it wears away more at the corners than at other points. To overcome this tendency of the digging edge to curl and to wear away at its corners, I provide the side wings 21 which connect the digging point 11a with the back wall 17 of the boss-receiving socket. Such Wings 21 also reinforce the boss receiving socket 17, 18 etc., and the portion of member 11 in advance of said socket.

In service, the resultant line of force from the digging point 11a is indicated by reference character A, such line being extended into the boss 15 so that digging stress is absorbed by the base section 10 and the lip which carries it. Such resultant force line A is, as will be noted, very close to being perpendicular to the socket wall 17 and end of the boss 15.

Also, such socket wall 17 will be substantially perpendicular to the ground when the bucket equipped with teethin accordance with my inventionis dropped to the ground preparatory for commencement of the digging operation.

From the foregoing it will be seen that digging stress is absorbed by the base section boss 15 and hence by the base section. Thus, no load-withstanding fastening means is necessary in the attachment of the digging section 11 to the base section and a simple bolt and nut 24, 25 may be employed to hold the sections 10, 11 in assembly. This saves the cost of expensive shank formations, etc., customarily used in attaching a digging point to a tooth base.

Also, referring to FIGS. 2 and 3, the tail section 23 of the digging point-providing member 11 preferably has a lug 26 engaged in a seat or recess 27 which is provided in the top portion 12 of the base section 10.

The tail portion 28 of the point-providing section 11, overlying as it does, the top surface part 12a of base section 10 cooperates with the boss and socket 15, 16 to prevent any'tendency to the section 11 to rock clockwise (FIGS. 1 and 2) in case the bucket is vertically dropped at the digging angle shown and the forward portion of 11 contacts hard rock.

Furthermore, the tail portion 23 of the point-providing section 11 provides a protective shield for the forward tip portion of base section 10. Also, the interengaging lug and seat 26, 27 provides a stress sustaining means which is secondary to the engaging top shoulders 22, 12b of the boss and socket structure 15, 16.

Referring again to boss 15, it primarily absorbs the digging stress from digging point 11a because the thickness of said boss in a top-to-bottom direction is such, in relation to the distance, from the outer end thereof to digging point 11a, that the line of digging stress A from said digging point 11a will pass into said boss 15 at all working angles of the tooth 10, 11 in relation to the surface of the material being dug, as indicated in FIGS. 1 and 2. Thus, there is never any real load on the bolt 2 although some digging stress will be absorbed by the shoulders 12b, 13b, 20 (and particularly 13b) which surround boss 15, such stress being transmitted thereto by said wings 21, 21. Also the recited arrangement with wings 21, 21 makes for a, tremendous saving of metal without sacrifice of tooth point strength.

Having thus described my invention what I claim is:

A digging tooth for excavating dippers' and the like comprisinga dipper lip-carried base section and a removable digging point-providing section carried as an extension of said base section, a boss of minor length as compared to the length of each of said sections and projecting substantially axially from and constituting the major portion of the front end of said base section; said boss having its bottom outer end edge disposed above but adjacent the plane of, the proximate bottom surface portion of said base section, said boss being offset below the plane of theupper surface of the base section to define a superjacent base section-provided shoulder; the top surface of said boss commencing at said shoulder being forwardly inclined toward the tooth axis and terminating in a substantially plane and vertically elongated digging loadsustaining outer end surface of an area not materially less than the maximum cross sectional area of said boss and disposed substantially normal to the longitudinal axis of said tooth; said digging point-providing section comprising a downwardly inclined main bar-like body portion having its rear portion contiguously supported by the inclined top surface of said boss with its rear end bearing against said base section shoulder, said main bar-like body portion terminating in a digging point at its outer end in advance of said boss and in close adjacency to the plane of the longitudinal axis of the tooth; a rearwardly opening boss-receiving and sustained socket integral with and having its top wall formed by the under rear portion of said bar-like body portion, said socket providing a back wall substantially perpendicular to the tooth axis; longitudinally extending and reinforcing side wings carried by the lower surface of the bar-like portion and connecting opposite sides of the digging point with related sideadjacent portions of the perpendicular socket back wall throughout substantially its depth, whereby the resultant force lines from said digging point in service terminate in the substantially plane vertically elongated end surface of said boss when the tooth is disposed at substantial angles with respect to the work; fastening means connecting said socket and boss, said bar-like main body portion providing a rearward extension of reduced thickness protectively and contiguously overlying the top base section surface rearwardly of said base section shoulder to also cooperate with said boss and socket to resist upward rocking of the digging point-providing section in service, and interengaging lug and seat means carried by said contiguous extension and base section surfaces and cooperating with said fastening means to maintain said base and digging point-providing sections assembled.

References Cited in the file of this patent UNITED STATES PATENTS Re. 12,608 Thomas Feb. 12, 1907 935,147 Gardner Sept. 28, 1909 1,016,181 Snyder Jan. 30, 1912 1,205,969 Brinton Nov. 28, 1916 1,384,701 McMonegal July 12, 1921 1,808,311 Madonna June 2, 1931 2,005,016 Van Buskirk June 18, 1935 2,032,875 Graham Mar. 3, 1936 2,167,425 Page July 25, 1939 2,213,925 Van Buskirk Sept. 3, 1940 2,259,456 Crawford Oct. 21, 1941 2,483,032 Baer Sept. 27, 1949 

